No doubt the train scene was impressive, the only thing missing from it for me was a shaking floor like they have at the Dungeons for a bit of physical feedback. It's a shame they couldn't get it to work right. I don't think it was mainly about removing actors. If they wanted to save money on the ride already, I doubt they would have changed the layout of the attraction two years in a row. I still think it's very much an ongoing project trying to create a new type of VR based attraction. I think they're very close with the live VR scenes.
For full immersion, I still reckon AR would be so much better. Have screens as the train windows and more reliable, high-def headsets. I know it would be even more expensive to do this but I think it would really mess with your mind about what is and isn't real. Imagine taking your headset off after the first scene and still seeing a demon hiding in the corner of the platform through the train windows before going out onto it. It's unlikely to happen I know but I can dream! That would be the best experience with the current technology imo.